<html><head>
  <title>Syntax and parsing of unknown pseudo-classes</title>
  <style type="text/css">
  p { background: lime; }
  p:subject { background: red; } /* this is not valid CSS, and if UAs
  implemented the experimental :subject pseudo-class they should have
  used the :-vnd-ident syntax. */
</style>
  <link rel="author" title="Ian Hickson" href="mailto:ian@hixie.ch">
  <link rel="help" href="https://www.w3.org/TR/css3-selectors/#selectors"> <!-- bogus link to make sure it gets found -->
  <link rel="match" href="reference/this-line-lime-background.xht">
  <meta name="flags" content="">
 </head>
 <body>
 <p>This line should have a green background.</p>

</body></html>